1988 Mercedes Benz 300e Sluggish, Slow To Start From Stop

Hi!

I bought a Mercedes 300E this past summer. I received it in a good condition with according to the owner, new plug wires (They look new) and a Valve Cover Gasket oil leak.

I'm a student so I don't have much money, I drove the car regularly until I experienced performance issues.
Mainly a HUGE loss of power and acceleration. The car takes about 15 seconds to go 0-60. It feels sluggish, when I press on gas, the engine feels like it has all this power but it's not releasing it, I got about 14-18MPG.

I started a tune-up and did:
I changed
-Spark Plugs (which needed to be changed)
-Fuel Filter
-Oil Filter/Oil
-Checked Air Filter. It's Fine

Drove the car, the problem is still persistent but now I'm getting about 22MPG.

Now today the problem is bigger, the car is taking longer to get to 60MPGs, it struggles to get acceleration. Once it makes it to 60 it's pretty smooth, but getting there (even while flooring it) is an issue.

Also, it gets wiped out by even slight hills, taking a lot of pressing on the pedal to get it going.

I've been told it could be a cap/rotor and/or the timing chain not matched perfectly.